My Spanish is mostly Rioplatense-based so I typically use “ustedes”. I do try to memorise the verb conjugations for “vosotros” though, mostly for reading/listening.

Then for the singular I typically use “vos” most of the time, and “usted” in the formal. I don’t know exactly the rules; frankly I simply hack it through Portuguese, if I feel like I’d call the person “o/a senhor[a]” I use “usted”, otherwise I use “vos”. But just like the above I try to memorise the “tú” conjugations.

I don’t think you can count your reference as that of a native speaker from Spain. Vosotros is second person plural and usted/ustedes is the formal/polite way to address someone, using the grammar of third person (singular or plural).

The other uses of vos(otros) and usted(es) are only coming into the picture with latin america. In Castellano, the grammar is clear.

So in reference to your “we use vosotros” - you use both, but for differenr purposes.